>From edd368e7436e7a80c5a43e7ad40cff1f3fa20806 Mon Sep 17 00:00:00 2001
From: Ming Lei <tom.leiming@xxxxxxxxx>
Date: Fri, 14 May 2010 17:35:51 +0800
Subject: [PATCH 2/2] ath9k: fix dma sync in rx path(v2)
If buffer is to be accessed by cpu after dma is over, but
between dma mapping and dma unmapping, we should use
dma_sync_single_for_cpu to sync the buffer between cpu with
device. And dma_sync_single_for_device is used to let
device gain the buffer again.
v2: Felix pointed out dma_sync_single_for_device is needed to return
buffer to device if an unsuccessful status bit check is found.
Signed-off-by: Ming Lei <tom.leiming@xxxxxxxxx>
Signed-off-by: Felix Fietkau <nbd@xxxxxxxxxxx>
---
drivers/net/wireless/ath/ath9k/recv.c | 10 +++++++---
1 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index a3fe6e1..f4453f0 100644
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -694,12 +694,16 @@ static bool ath_edma_get_buffers(struct ath_softc *sc,
bf = SKB_CB_ATHBUF(skb);
BUG_ON(!bf);
- dma_sync_single_for_device(sc->dev, bf->bf_buf_addr,
+ dma_sync_single_for_cpu(sc->dev, bf->bf_buf_addr,
common->rx_bufsize, DMA_FROM_DEVICE);
ret = ath9k_hw_process_rxdesc_edma(ah, NULL, skb->data);
- if (ret == -EINPROGRESS)
+ if (ret == -EINPROGRESS) {
+ /*let device gain the buffer again*/
+ dma_sync_single_for_device(sc->dev, bf->bf_buf_addr,
+ common->rx_bufsize, DMA_FROM_DEVICE);
return false;
+ }
__skb_unlink(skb, &rx_edma->rx_fifo);
if (ret == -EINVAL) {
@@ -808,7 +812,7 @@ static struct ath_buf *ath_get_next_rx_buf(struct ath_softc *sc,
* 1. accessing the frame
* 2. requeueing the same buffer to h/w
*/
- dma_sync_single_for_device(sc->dev, bf->bf_buf_addr,
+ dma_sync_single_for_cpu(sc->dev, bf->bf_buf_addr,
common->rx_bufsize,
DMA_FROM_DEVICE);
--
1.6.2.5
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